If you are using Sitecore 8.2 Update 1 or later, Sitecore has official support for Azure Search: https://doc.sitecore.net/sitecore%20experience%20platform/setting%20up%20%20maintaining/search%20and%20indexing/sitecore%20azure%20search%20overview

A new search provider to use in place of the default Lucene search provider in Sitecore 8.1. This provider uses Azure Search, which is a cloud based search provider, as opposed to the file based, Lucene search provider. See the Issues tab or the Wiki for information on current issues.

Prerequisites:

• You will need to have a Sitecore 8.1 instance installed
• Visual Studio 2015
• Sitecore Instance Manager (Used to create the Visual Studio solution)
• Azure Subscription with an Azure Search instance
• Follow the instructions in the root folder's Readme.txt file.

Sitecore 8.1 Azure Search Provider The MIT License (MIT)

Copyright (c) 2016 Jamie Scott

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.